The Washoe County Sheriff’s Department and Nevada Highway Patrol are testing out a new device to let motorists know they need to get out of the way.

Not just know it — but feel it, too.

The device, called “The Rumbler,” is a low-frequency supplement to the traditional sirens. The device senses the siren’s signal, reduces the signal’s frequency by 75 percent and amplifies the sound through a pair of high output woofers mounted beneath the car.

“The idea came up that people were cocooning themselves so much inside their vehicles that in some cases, the siren and lights didn’t seem to be enough,” said Tom Morgan, police market vice president at Federal Signal Corp., which produces The Rumbler.

The low-frequency tones are supposed to penetrate and shake solid materials so vehicle operators and nearby pedestrians will feel the sound waves, and may even see their effects through a shaking rearview mirror. The device is timed to last for eight seconds and is meant to be activated as an officer comes up on an intersection. The device has already seen action in other parts of the country, including St. Louis and Washington, D.C., where it is expected to be installed on almost 800 cars over the next four years.

“As cops we’re all frustrated by the same thing: People not recognizing that we’re approaching. Whether it’s at an intersection or on the freeway it’s amazing how many people don’t see the lights or hear the sire,” said Sgt. Eric Spratley, of the Washoe County Sheriff’s Department research and development unit.

Spratley said one sheriff’s car and one NHP car have been outfitted with The Rumbler will be studied in northern Nevada for possible installation on more cars. Spratley said they will be checking to see if the device can stand up to the extreme weather conditions of northern Nevada and whether the sound produced has the intended effect of getting the attention of more motorists. Spratley said that deputies will be reporting their observations on reactions to The Rumbler so the department can decide if is worth spending $600 per unit to install on 60 sheriff’s vehicles.

“If it helps avoid one T-bone crash, it will pay for the entire fleet,” Spratley said.